Frictional retainer for excavator tooth key



1968 G. A. PETERSEN 3,413,740

FRICTIONAL RETAINER FOR EXCAVATOR TOOTH KEY Filed Dec. 20, 1965INVENTOR. GERALD A. PETERSEN A T TORNEV United Smtes Patent 3,413,740FRICTIONAL RETAINER FOR EXCAVATGR TGOTH KEY Gerald A. Petersen,Sunnyvale, Calif, assignor of one-half to Anita E. Petersen, Saratoga,Calif.

Continuation-impart of application Ser. No. 485,154,

Sept. 7, 1965. This application Dec. 20, 1965, Ser.

3 Claims. (Cl. 37142) ABSTRACT OF THE DISCLOSURE A key passes throughaligned holes in a tooth-holder and fits into a notch in the tooth,thereby restraining withdrawal of the tooth from the holder. To preventthe key from being jarred loose, a rubber loop extends around the keyand frictionally engages Walls of the holder and of the tooth.

This invention is a continuation-in-part of copending application Ser.No. 485,154, now Patent No. 3,349,508, filed Sept. 7, 1965, and relatesto a frictional retainer for excavator tooth key.

Excavating equipment, of which a typical example is a dipper bucket,employs replaceable teeth formed to mate with tooth-holders which areeither integral with or fastened to the bucket or other portion of theequipment. As a tooth becomes worn, it is necessary to disengage it fromits tooth-holder for replacement, sharpening, or repair, and the art hasdeveloped various means for holding a detachable tooth and for retainingthe tooth in place against unintentional dislodgment. The presentinvention comprises an improvement on such means. Thus in the prior art,one means for a retaining tooth in place is the use of a key insertedthrough an aperture in the tooth-holder and passing through an alignednotch or hole in the tooth. The key restrains withdrawal of the toothrelative to the holder. Such a key may be of various cross-sectionalshapes and may be straight or tapered and this invention contemplatesuse of various shapes of keys. Because of the severe operatingconditions to which excavating teeth are subjected, repeated stressesmay cause the key to be dislodged with consequent unintentionalseparation of the tooth and holder. The present invention comprises ameans for restraining dislodgement of the key.

More specifically, the present invention provides a retainer of rubberor rubber substitute, which is compressed between the key and adjacentwall of the apertures or notches in the tooth and/ or holder throughwhich the key passes. The rubber frictionally restrains unintentionaldislodgement of the key. However, when it is necessary to remove thetooth the key may be driven out of its socket by means of a hammer orprying instrument against the resistance of the retainer.

In a preferred form of the invention, the retainer heretofore describedis a length of circular cross-sectional rubber or rubber-like materialwhich is bent in a U- shape passing around at least two sides and oneend of the key. When the key is driven into the socket, the entering endof the key forces the center of the U-shaped portion down into thesocket, pulling the legs of the U- shaped portion along with the key.The legs are then compressed between the key and adjacent walls andrestrain withdrawal of the key.

In a further preferred form of the invention, shallow grooves may beformed in the wall of the socket facing the key, the depth of suchgrooves being less than the initial cross-sectional shape of the rubber.Hence the rubber is compressed between the bottom of the groove and theadjacent face of the key. Deformation of the Patented Dec. 3, 1968rubber in this manner enhances the frictional resistance to withdrawalof the key and makes for more effective retention. Further, theconstruction heretofore described accommodates variations in dimensionsof the parts.

Bending the retainer as heretofore described insures that it is notpulled out of position, since the tension on each of the two legs isapproximately the same.

In another preferred form of the invention the retainer is in the formof a closed loop, such as an O-ring. The ring fits over each end andalong opposite sides of the key.

Although straight and tapered keys of rectangular cross-section havebeen most commonly used in the excavating tooth art, the presentinvention is also used with keys of other cross-sections, such as round,oval or diamond-shape.

In one form of the present invention, the rubber may be fused,vulcanized, or cemented to the key. However, such permanent attachmentof the rubber to the key is not necessary since long lengths of rubbermay be stocked by the users of excavating equipment and individuallengths of proper size cut from a coil of rubber as required.

The present invention is usable with a wide variety of excavatingequipment. Various manufacturers use different configurations of theproximal portions of the teeth and the mating portions of thetooth-holder. Two such shapes are hereinafter described in detail andthe invention is particularly useful with such designs. However, theinvention has wider applicability to numerous other shapes employingtransverse keys.

Other objects of the present invention will become apparent upon readingthe following specification and referring to the accompanying drawingsin which similar characters of reference represent corresponding partsin each of the several views.

In the drawings:

FIG. 1 is a fragmentary top plan view of portion of a tooth andtooth-holder, in accordance with this invention.

FIG. 2 is a sectional view taken substantially along the line 22 of FIG.1.

FIG. 3 is an enlarged fragmentary sectional view of a portion of thestructure taken substantially along the line 3-3 of FIG. 2.

FIG. 4 is a side elevational view of one form of key, in accordance withthe invention.

FIG. 5 is an end elevation of the strutcure of FIG. 4.

FIG. 6 is a sectional view of a modification employing a tapered key,the line of the section being indicated by line 66 of FIG. 2.

FIGS. 7 and 8 are, respectively, similar to FIGS. 4 and 5 of the taperedmodification.

FIG. 9 is a view similar to FIG. 1, showing the invention applied to adifferent form of tooth and toothholder.

FIG. 10 is a view similar to FIG. 3 of the modification of FIG. 9.

FIG. 11 is a view similar to FIG. 5 of a modified retainer.

FIG. 12 is an enlarged fragmentary sectional view taken substantiallyalong line 1212 of FIG. 11.

FIGS. 13 and 14 are fragmentary perspective views of two furthermodified keys.

Tooth 11 and tooth-holder 12, shown in FIGS. 1 to 3, are similar in manyrespects to those corresponding elements shown in said Ser. No. 485,154.Tooth 11 has a distal portion 13 and proximal portion 14. Distal portion13 is subject to considerable variation. In the form herein shown, thereare outwardly converging top and bottom surfaces 16 and the top surfaceis formed with a medial longitudinal rib 17, which slantsdownward-forward toice ward top surface 16 and merges therein at aterminus 18, spaced reaward from the blunt transverse perpendicularforward end 19 of the tooth. The side edges 21 of distal portion arevertical and parallel and are spaced apart approximately the samedistance as the sides 22 of holder 12.

Immediately forwardly of holder 12 are laterally extending protuberances23 on either side of the rearward end of longitudinal rib 17 which, ineffect, comprise a transverse rib. Protuberances 23 have an elevation atleast as high as rib 17 and the top edge of rib 24 of proximal portion14. Corners 26 where rib 17 and protuberances 23 coincide are roundedand filleted to direct dirt dug by the front cutting edge 19 sidewardly.Protuberances 23 limit inward movement of the tooth relative to holder12 and insure that the tooth seats against the front end of the holderand not at the back of the holder. Although this feature of theinvention is optional, nevertheless it avoids undue strain at the pointwhere the front of the holder and tooth coincide, and in the event ofthe corner of the tooth hitting a rock or other hard object with greatforce might cause a fracture or dislodgment of the tooth.

Proximal portion 14 of tooth 11 is of an inverted T- shape incross-section and narrower than the distal portion. It has an upwardlyextending rib 24 and laterally projecting legs 27a on opposite sides andbelow rib 24. Legs 27, 27a extend in a rearward extension 28 behind therearward end of rib 24. Extension 28 enhances the stability of the toothin its holder. The elevation of rib 24 relative to the top of holder 12is subject to considerable variation, as is explained in Serial No.485,154.

Holder 12 has a forward opening socket complementary to thecross-section of the proximal portion 14 of tooth 11. Thus holder 11 hasa bottom 31, having a bottom wall 32 against which the bottoms of legs27 rest, and also sides 33, 33a and overhanging lips 34, 34a separatedby a longitudinal vertical slot 36 in the top of holder 12 through whichrib 24 projects.

Installation and removal of tooth 11 from holder 12 results in theproximal portion 14 sliding in the recess in holder 12.

The retention means shown in FIGS. 1 to comprises a key 36, which isstraight and rectangular in shape. A rectangular aperture 37 is cut inholder 12, intersecting leg 27a and a rectangular notch 38 is formed inleg 27a. Thus when key 36 is driven into aperture 37, it also entersinto notch 38 and hence locks the tooth in the holder. The disadvantageof metal keys of the type thus described has heretofore been that theytend to be dislodged by vibration and other forces. Various means forretaining the keys in their holes have been proposed, but such meanshave been unsatisfactory in the sense that they are either ineffectiveor make installation and removal time-consuming.

In accordance with a preferred form of the present invention, a lengthof circular cross-section rubber 41 is used. A synthetic rubbermaterial, such as neoprene or other synthetic material may be used,certain of such synthetics being particularly useful where hightemperatures are encountered. Preferably, the rubber length 41 is bentin U-shape, as best shown in FIG. 5, the bottom stretch 42 underlyingthe bottom end 43 of key 36 and sides 44 extending up along sides 46 ofthe key. Rubber 41 may be cut in the field from a coil, kept by the userfor such purpose, or it may be fused, vulcanized or cemented in variousways to key 36. To accommodate rubber 41, shallow grooves 47 may beformed in walls of aperture 37, preferably of a depth less than theinitial cross-sectional area of rubber 41 so that the rubber is deformedand compressed, augumenting frictional resistance to withdrawal of thekey from its socket. Such deformation of the rubber also accommodatesminor variations in dimensions of the parts.

The key is installed by bending the rubber to the shape best shown inFIGS. 4 and 5 and then inserting the lower end 43 of key 36 in theaperture 37 and driving the same down until it assumes the position bestshown in FIG. 2. The key enters andfills the notch 38. The key normallyremains in place against unintentional dislodgment despite considerablevibration and other stresses tending to separate the members. When it isnecessary to remove tooth 11, an instrument may be inserted through thebottom of hole 37, driving the bottom end 43 upwardly against thefrictional resistance of rubber 41 until the key clears notch 38,permitting tooth 11 to be slid out of holder 12 longitudinally. Themodification of FIGS. 6 to 8 resembles that heretofore described, exceptthat key 36b is tapered and the hole 37b and notch 38b are similarlytapered. Thus one edge 51 of key 36b is straight, while the oppositeedge 52 is tapered. Rubber 41b extends around edges 51, 52 and bottom43b in stretches 44b, 42b.

In use in the modification of FIGS. 6 to 8, tapered key 36b when driveninto holes 37b and notch 38b draws tooth 11 into position withprotuberances 23 snug against the forward end of the holder. The rubberretainer 41b functions in .a manner similar to that previouslvdescribed.

The modification of FIGS. 9 and 10 shows the invention applied to aprolonged tooth 110, similar to that shown in Petersen Patent No.2,968,880. The distal portion 130 of tooth 11c is subject to widevariation but, as shown in fragmentary form in FIG. 9, resembles thedistal portion 13 of FIG. 1. The proximal end of the tooth is dividedinto two prongs 61, each substantially rectangular in cross-section bymeans of a rectangular slot 62 which extends forwardly from the rearwardend of the tooth, the walls of slot 62 being substantially vertical andparallel and terminating at a front end 63. A web 64 extends from top tobottom of holder 12c, substantially complementary to slot 62. Holder120, as viewed from the forward end, is generally of the shape of theletter H turned on its side. This shape is shown in the Petersen patentheretofore mentioned and is now very common in the art. The presentinvention provides an alternate means for holding the tooth and holdertogether. Thus a hole 370 is formed in holder through the web 64, hole37c also overlapping the interface indicated by reference numeral 66,where the wall of Web 64 faces the inner Wall of slot 62. A notch 38c isformed in a prong 61. Key 36c is similar to that heretofore describedand is driven into hole 380 and notch 370. In shape, key 360 mayresemble either that shown in FIGS. 4 and 5, or FIGS. 5 to 7, and theholes and notches 37c, 380 are formed complementary thereto. Similarly,rubber 41c extends around the sides and bottom of key 360 and iscompressed within shallow groove 47c, communicating with holes 370. Therubber 41c retains key 360 in position as in the preceding modification.

It will further be understood that whereas in the accompanying drawingsa single key 36 has been shown for each tooth and holder, more than asingle key may be used where operating conditions are severe. It willfurther be understood that although the keys are shown in theaccompanying drawings in what are presently deemed to be the mostsuitable locations, they may be applied in other locations. Thus thekeys may extend transversely of the direction shown, or may be locatedin different areas. Also, as has been stated, the principle of therubber retainer for the key may be applied to other shapes of teeth andholders.

As shown in FIGS. 11 and 12, instead of an openended length of rubber 41a closed loop 41d may be used, such as an O-ring. Preferably thecircumference of ring 41d is slightly less than the periphery of the key36a so that ring 41d is stretched slightly when slipped over each end43d and down opposite sides 46d of key 36d.

In FIG. 13, the cross-sectional shape of key 362 is round rather thanrectangular. It will be understood that key 36e may be tapered ratherthan straight and that retainer 41e may be either an open-ended loop (asin FIG. 1) oraring (as inFIG. 11).

FIG. 14 shows a diamond cross-sectional key 36 with retainer 41 Theremarks applicable to FIG. 13 are likewise applicable here.

Although the foregoing invention has been described in some detail, byway of illustration and example for purposes of clarity ofunderstanding, it is understood that certain changes and modificationsmaybe practiced within the spirit of the invention and scope of theappended claims.

What is claimed is:

1. The combination of a tooth having a distal cutting portion and aproximal portion, a tooth-holder formed with a recess opening forwardand shaped to receive said proximal portion, said tooth and holderformed with aligned apertures, said apertures being formed with at leastone shalow groove, a rigid elongated key member fitting through saidaligned apertures to restrain withdrawal of said tooth from said holder,and a resilient retainer compressed between walls of said apertures andsaid key member to restrain unintentional withdrawal of said key fromposition through said apertures, said retainer being partially withinsaid groove and extending longitudinally of said key and engaging wallsof said holder and of said tooth.

2. The combination of a tooth having a distal cutting longitudinally ofsaid key and engaging walls of said holder and of said tooth, saidproximal portion of said tooth being T-shaped in cross-section, one saidaperture comprising a notch in the outer edge of a foot of said T, theother said apertures comprising holes in said holder.

3. The combination of a tooth having a distal cutting portion and aproximal portion, said proximal portion of said tooth being bifurcatedin a pair of prongs, each substantially rectangular in cross-section anddivided by a longitudinal slot, a tooth-holder formed with a recessopening forward and shaped to receive said proximal portion, said toothand holder formed with aligned apertures, one said aperture comprising anotch in a wall of said slot, the other said apertures comprising holesin said holder, a rigid elongated key member fitting through saidaligned apertures to restrain withdrawal of said tooth from said holder,and .a resilient retainer compressed between walls of said apertures andsaid key member to restrain unintentional Withdrawal of said key fromposition through said apertures, said retainer extending longitudinallyof said key and engaging walls of said holder and of said tooth.

References Cited UNITED STATES PATENTS 1,951,988 3/1934 Mekeel.2,222,071 11/1940 Gustafson 37-l42 2,253,245 8/1941 Noack 371422,657,482 11/1953 Launder et al. 2,982,035 5/1961 Stephenson.

ABRAHAM G. STONE, Primary Examiner.

A. E. KOPECKI, Assistant Examiner.

